The present invention relates to a board cleaning method and a board cleaning apparatus for dry cleaning of connection sites on resin-based boards, and a component mounting method for placing electronic components onto these cleaned resin-based boards. Herein, “component mounting method” refers to a method for performing board cleaning and performing placement of electronic components onto cleaned boards. Additionally, “component mounting apparatus or system” refers to an apparatus or a system for performing board cleaning and performing placement of electronic components onto cleaned boards.
With miniaturization of portable telephones, PDA and the like, in recent years, flexible printed circuit boards (which will be referred to as “FPC” (Flexible Printed Circuit), hereinbelow) have been used for internal electric circuits, and direct placement of IC (Integrated Circuit) bare chips (which will be referred to as “IC chips,” hereinbelow) onto FPC has been performed.
Electrodes of IC chips are formed with extremely narrow pitches, and adhesive material containing conductive minute particles is used in placement of such IC chips. More specifically, the adhesive material is applied onto an FPC, IC chips are placed thereon, and heat is applied thereto while the IC chips are pressed against the FPC. This operation crushes the conductive minute particles in the adhesive material between the IC chips and the FPC, and makes electric connections between the electrodes of the IC chips and wiring on the FPC. The adhesive material is cured by application of heat.
With increase in degree of integration of circuits in IC chips, pitches of electrodes formed on IC chips have been being narrowed further. Accordingly, pitches of wiring lines that are formed on FPC are required to be further miniaturized. Such miniaturization of the pitches of the wiring lines causes issues such as deterioration and short circuit in the wiring that are caused by ionic migration. Ionic migration refers to deterioration in wiring that is caused by repetitive action of ionization and deposition of wiring metal by moisture absorption. It is known that ionic migration is promoted by chloride residue produced in a plating process in production of FPC.
As pitches of wiring lines have been narrowed, on the other hand, it has been becoming impossible to neglect influences of deposition on wiring of minute organic matter such as skin, scurf, and cosmetics from a human body, or flux, oil, and resin pieces floating in a factory.
Therefore, the present invention has been devised in view of these issues, and an object of the present invention is to provide a board cleaning method, a board cleaning apparatus, and a component mounting method that are capable of improving reliability of connection with resin-based boards and, in particular, an object of the present invention is to provide a board cleaning method, a board cleaning apparatus, and a component mounting method that are capable of achieving improvement in strength of connection by activation of a board surface, suppression of occurrence of ionic migration in wiring formed on boards, and the like.